JPS60167615A - Gas insulated electric device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to gas insulated electrical equipment, and in particular, to a gas insulated electrical equipment having a structure suitable for alleviating reduction in dielectric strength of the equipment even when conductive foreign matter is mixed in. Regarding electrical equipment.

[Background of the invention]

Gas-free electrical equipment is often used with a configuration in which a high-voltage structure such as a current-carrying conductor is placed inside a metal tube sealed with negative gas, with a gas space. When conductive foreign matter gets mixed in and falls and accumulates at the bottom of the tube, the conductive foreign matter floats up from the tube surface depending on the applied electric field and floats in the gas space, causing the gas space dielectric strength to decrease. is in a situation where it is declining significantly. In order to ensure the insulation reliability of equipment, it is desired to have equipment with a configuration that can prevent the effects of this conductive foreign material.

One way to solve this problem is to form an insulating layer with a high dielectric constant on the inner surface of the tube, which has a strong electrostatic attraction force that can withstand the electrostatic levitation blades that act on conductive foreign objects when electricity is applied. There are some devices that are designed to suppress the floating movement of conductive foreign objects, because the electric current acts between the conductive foreign objects and the bottom of the tube. in this case,
The insulating layer needs to be formed using a high dielectric constant material whose dielectric constant is larger than a predetermined value. Until now, thin film sheet-like members have been used as insulating layer forming members that satisfy this condition.

Alternatively, fixed plate-like members have been considered, but these members still have problems when fixedly installed on the inner surface of the tube. In other words, does fixed installation on the inner surface of the pipe give adhesiveness to the back surface of this member?

Alternatively, a method has been adopted in which the same end of this member is adhesively fixed with an adhesive member, but this fixed installation method has a concern that peeling may occur due to the longevity of the adhesive force.

[Purpose of the invention]

An object of the present invention is to provide a gas-insulated electric device in which an insulating layer that can be semi-permanently fixed tightly to the inner surface of a tube body is formed by increasing the vi current of the insulating layer and improving its installation method.

[Summary of the invention]

The present invention provides that the dielectric constant of a coating layer formed from a liquid mixture in which fine powder of a high dielectric constant member is dissolved as a filler can be adjusted to IIa according to the mixing ratio of the filler and the dielectric constant of the filler. Moreover, it was confirmed through experiments that the levitation effect of conductive foreign matter placed on the coating layer formed with a dielectric constant of 10 or more is suppressed, and a thin high dielectric constant insulating layer is semi-permanently applied to the inner surface of the device. As a means of stably installing it, it is formed by a coating layer of a mixed liquid.

[Embodiments of the invention]

The embodiments of the present invention will be described above.

As shown in FIGS. 1 and 2, a gas-insulated electrical system is constructed by arranging a high-voltage conductor 3 insulated and supported by an insulating support 2 in a grounded metal tube l, and sealing an insulating gas. In the device, the high-permittivity insulating layer 4 formed on the inner surface of the tube l is formed by a coating layer coated with a mixture of a binder liquid and a fine powder of a ferroelectric material dissolved therein.

For the conductive foreign matter 5 and 6 that fall and accumulate on the insulating layer 4, an electrostatic attraction force that can resist the electrostatic levitation blade depending on the applied electric field acts between the conductive foreign matter and the bottom of the tube body.

The levitation effect of conductive foreign objects 5 and 6 mixed into the equipment is prevented.

In order to obtain an electrostatic attraction force that effectively prevents the floating action of conductive foreign matter, the dielectric constant of the insulating layer must be greater than 10, but the dielectric constant is greater than the dielectric constant of the binder liquid and filler. It is determined by the ratio and further by the mixture of the two.

Figure 3 shows a general exterior paint stock solution (
The relationship between the mixing ratio and the relative dielectric constant of the coating layer formed from the mixed liquid ↓ is shown when fine powder of titanate barium porcelain is used as a filler (40% solvent, 60% raw material). The relative dielectric constant ε of the coating layer can be increased by increasing the mixing amount ω of the filler, and the condition of ε1≧10 is ω≧20 (%, voQ)
This can be achieved with Further, the third-same relationship changes mainly depending on the dielectric constant of the filler, and by using a filler with a large dielectric constant, ε1 can be effectively increased.

Further, it is desirable that the binder liquid has a strong coagulating power, so that the adhesiveness of the coating layer to the inner surface of the tube is strengthened, and the effect that the insulating layer 4 can be stably installed semi-permanently can be obtained.

In addition, by using anti-rust paint etc. as a binder liquid for the purpose of protecting the metal surface, the insulating layer can be
The effect of providing metal surface protection functions such as rust prevention can be obtained.

In addition, by applying a DC electric field to the insulating layer 4 and subjecting it to polarization treatment, the dielectric constant of the insulating layer 4 can be further increased, so that the electrostatic attraction force can be further increased. Fourth
The figure shows the floating electric field of a conductive foreign object placed on an insulating layer (the electric field strength inside the tube body in terms of applied voltage when a conductive foreign object floats; "t, o").
) and v DC electric field Eoc during polarization processing. When EDC = 2-, the ELO is significantly improved compared to the former two, and the effect of forming an insulating layer can be efficiently achieved by satisfying the condition of a bare electrode (metal that does not form an insulating layer) shown by the dashed line in Figure 1. It can be demonstrated.

〔Effect of the invention〕

According to the present invention, the insulating layer can be easily formed on the inner surface of the tube by spray coating with filler-mixed binder liquid, the means for forming the layer is significantly simplified, and the adhesion to the inner surface of the tube is strengthened. be.

[Brief explanation of the drawing]

1 and 2 are a cross-sectional view and a vertical cross-sectional view of a gas insulated device, and FIG. 3 is a diagram showing the relationship between the mixing ratio of the binder liquid and the filler and the dielectric constant. DESCRIPTION OF SYMBOLS 1... Metallic pipe body, 2... Insulating support body, 3... High voltage conductor, 4... Insulating layer. Agent Patent Attorney Akio Takahashi ■ III (nearly 0%) ED, c (~-n Procedural Amendment (1 礪) 1115%”11?,! Patent Office Commissioner Kazuo Wakasugi Case Display 1988 Patent Application No. Name of invention No. 21729 Relationship to the case of person amending gas-insulated electrical equipment Patent applicant name Name 45101 Hitachi, Ltd. Publication person

Claims (1)

[Scope of Claims] 1. In an electrical device in which an insulated and supported high-voltage conductor is inserted into a metallic tube sealed with negative gas, and an insulating layer is formed on the inner surface of the metallic tube, a powdered ferroelectric 1. A gas-insulated electric device, characterized in that an insulating layer is formed by a coating layer of a liquid mixture obtained by mixing and dissolving a material. 2. The gas-insulated electric device according to claim 1, wherein the insulating layer has a metal surface protection function. 3. A gas-insulated electric device according to claim 1, characterized in that: v a direct current electric field larger than 2 is applied to the insulating layer to perform polarization treatment. 4. The gas-insulated electricity according to claim 1, wherein the insulating layer is formed by a coating layer in which the mixing ratio of the binder liquid and the filler is adjusted so that the dielectric constant is greater than 10. device.